Prevalence of myopia in school children in rural and urban regions of the Island of Cebu, Philippines.

Abstract

 

Purpose

 

Prevalence studies in various ethnic populations and geographical regions have increased our understanding of the roles of genetic predisposition and environmental exposure in the development of myopia. This study aimed to determine the prevalence of myopia in school children in rural and urban regions of the Island of Cebu, Philippines and to compare the prevalence of myopia between these two settings. We hypothesized that school children in rural regions would have a lower prevalence of myopia than those in urban regions.

 

Methods

 

Children at five selected schools were randomly sampled and stratified by age. Those children with amblyopia, strabismus or active eye infection and those children not of Filipino ethnic origin were excluded. Eye examinations were conducted by five teams of senior optometry students under the supervision of a professional optometrist. Visual acuity was assessed through use of Snellen, Lea’s Symbols, or Tumbling E Charts. Objective refraction was performed using a streak retinoscope and trial lenses. Subjective refraction was then performed on each child whose uncorrected visual acuity was less than 20/20. Myopia was defined as a spherical equivalent refractive error less than -0.5 dioptres. Logistic regression was used to determine the impact of setting on the development of myopia, while controlling for age and gender.

 

Results

 

A total of 1272 children were included in this study. The mean age of the rural cohort was 10.6 ± 2.79 years and that of the urban cohort was 9.93 ± 1.89 years. The proportion of male children was 51.5% in the rural cohort and 51.7% in the urban cohort. The overall prevalence of myopia was 5.04%. The prevalence of myopia in the rural cohort (3.00%) was observed to be significantly less than that in the urban cohort (12.5%, p < 0.001), and it tended to increase with age. Logistic regression demonstrated that those children in the rural setting were observed to be at a decreased risk for the development of myopia (OR 0.215, 95% CI 0.129 to 0.359).

 

Conclusions

 

This study provides the first estimates of the prevalence of myopia in those of Filipino ethnic origin. The prevalence of myopia was significantly less among school children in rural regions than among those in urban regions, supporting the impact of environmental exposure in the development of myopia.